COP1 and neoplasm: In order to find out the mechanism of the limited efficacy of ICB therapy for triple negative breast cancer (TNBC), Xiaoqing Wang et al. conducted an in vivo CRISPRko screen in the syngeneic TNBC mouse model and confirmed that the deletion of E3 ubiquitin ligase Cop1 in TNBC cells reduced the macrophage infiltration and the secretion of chemokines, led to enhancing anti-tumor immunity and improving the efficacy of ICB therapy for tumor (Wang X. et al., 2021).